Pore-size dependence of the self-diffusion of hexane in silica gels

2002 ◽  
Vol 116 (24) ◽  
pp. 10869-10876 ◽  
Author(s):  
J. Baumert ◽  
B. Asmussen ◽  
C. Gutt ◽  
R. Kahn
Keyword(s):  
Pore Size ◽  
Size Dependence ◽  
The Self ◽  
Silica Gels ◽  
Self Diffusion

DYNAMICS OF SIMPLE FLUIDS CONFINED IN CYLINDRICAL PORE: EFFECT OF PORE SIZE

2005 ◽  
Vol 04 (01) ◽  
pp. 305-315 ◽  
Author(s):  
HYUNGJUN KIM ◽  
CHUL HEE CHO ◽  
EOK KYUN LEE
Keyword(s):  
Pore Size ◽  
Particle Diameter ◽  
Simulation Method ◽  
The Self ◽  
Dynamics Simulation ◽  
Axial Component ◽  
Cylindrical Pore ◽  
Self Diffusion ◽  
Wide Range ◽  
Wall Interaction

We study the thermodynamic and dynamical properties of Weeks–Chandler–Anderson (WCA) fluids confined in a cylindrical pore by means of a canonical molecular dynamics simulation method. The pore model is an infinitely long cylinder consisted of a thermal wall and mimics a typical carbon nanotube. The thermodynamic properties are obtained for relatively high density fluids over a wide range of pore diameters at a given temperature. The size dependence of the self-diffusion coefficients in the cylindrical pore is also investigated. It is found that, as the pore diameter decreases, the potential energy and axial component of the pressure exhibit a sharp rise and the self-diffusion coefficient decreases. The observed behaviors can be understood in terms of the geometrical confinement and attenuation of transport induced by dispersive fluid-wall interaction. In addition, anomalous diffusion is observed at the pore size corresponding to twice the particle diameter.

scholarly journals Influence of Pore Size on Carbon Dioxide Diffusion in Two Isoreticular Metal–Organic Frameworks

2020 ◽  
Author(s):  
Alexander C. Forse ◽  
Kristen A. Colwell ◽  
Miguel I. Gonzalez ◽  
Stefan Benders ◽  
Rodolfo M. Torres-Gavosto ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Porous Materials ◽  
Pore Size ◽  
Critical Role ◽  
Metal Organic Frameworks ◽  
The Self ◽  
Self Diffusion ◽  
Common Strategy ◽  
Metal Organic ◽  
Different Diameters

The rapid diffusion of molecules in porous materials is critical for numerous applications including separations, energy storage, sensing, and catalysis. A common strategy for tuning guest diffusion rates is to vary the material pore size, although detailed studies that isolate the effect of changing this particular variable are lacking. Here, we begin to address this challenge by measuring the diffusion of carbon dioxide in two isoreticular metal–organic frameworks featuring channels with different diameters, Zn<sub>2</sub>(dobdc) (dobdc<sup>4–</sup> = 2,5-dioxidobenzene-1,4-dicarboxylate) and Zn<sub>2</sub>(dobpdc) (dobpdc<sup>4−</sup> = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), using pulsed field gradient NMR spectroscopy. An increase in the pore diameter from 15 Å in Zn<sub>2</sub>(dobdc) to 22 Å in Zn<sub>2</sub>(dobpdc) is accompanied by an increase in the self-diffusion of CO<sub>2</sub> by a factor of 4 to 6, depending on the gas pressure. Analysis of the diffusion anisotropy in Zn<sub>2</sub>(dobdc) reveals that the self-diffusion coefficient for motion of CO<sub>2</sub> along the framework channels is at least 10,000 times greater than for motion between the framework channels. Our findings should aid the design of improved porous materials for a range of applications where diffusion plays a critical role in determining performance.

scholarly journals Influence of Pore Size on Carbon Dioxide Diffusion in Two Isoreticular Metal–Organic Frameworks

2020 ◽  
Author(s):  
Alexander C. Forse ◽  
Kristen A. Colwell ◽  
Miguel I. Gonzalez ◽  
Stefan Benders ◽  
Rodolfo M. Torres-Gavosto ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Porous Materials ◽  
Pore Size ◽  
Critical Role ◽  
Metal Organic Frameworks ◽  
The Self ◽  
Self Diffusion ◽  
Common Strategy ◽  
Metal Organic ◽  
Different Diameters

The rapid diffusion of molecules in porous materials is critical for numerous applications including separations, energy storage, sensing, and catalysis. A common strategy for tuning guest diffusion rates is to vary the material pore size, although detailed studies that isolate the effect of changing this particular variable are lacking. Here, we begin to address this challenge by measuring the diffusion of carbon dioxide in two isoreticular metal–organic frameworks featuring channels with different diameters, Zn<sub>2</sub>(dobdc) (dobdc<sup>4–</sup> = 2,5-dioxidobenzene-1,4-dicarboxylate) and Zn<sub>2</sub>(dobpdc) (dobpdc<sup>4−</sup> = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), using pulsed field gradient NMR spectroscopy. An increase in the pore diameter from 15 Å in Zn<sub>2</sub>(dobdc) to 22 Å in Zn<sub>2</sub>(dobpdc) is accompanied by an increase in the self-diffusion of CO<sub>2</sub> by a factor of 4 to 6, depending on the gas pressure. Analysis of the diffusion anisotropy in Zn<sub>2</sub>(dobdc) reveals that the self-diffusion coefficient for motion of CO<sub>2</sub> along the framework channels is at least 10,000 times greater than for motion between the framework channels. Our findings should aid the design of improved porous materials for a range of applications where diffusion plays a critical role in determining performance.

scholarly journals Influence of Pore Size on Carbon Dioxide Diffusion in Two Isoreticular Metal–Organic Frameworks

2020 ◽  
Author(s):  
Alexander C. Forse ◽  
Kristen A. Colwell ◽  
Miguel I. Gonzalez ◽  
Stefan Benders ◽  
Rodolfo M. Torres-Gavosto ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Porous Materials ◽  
Pore Size ◽  
Critical Role ◽  
Metal Organic Frameworks ◽  
The Self ◽  
Self Diffusion ◽  
Common Strategy ◽  
Metal Organic ◽  
Different Diameters

The rapid diffusion of molecules in porous materials is critical for numerous applications including separations, energy storage, sensing, and catalysis. A common strategy for tuning guest diffusion rates is to vary the material pore size, although detailed studies that isolate the effect of changing this particular variable are lacking. Here, we begin to address this challenge by measuring the diffusion of carbon dioxide in two isoreticular metal–organic frameworks featuring channels with different diameters, Zn<sub>2</sub>(dobdc) (dobdc<sup>4–</sup> = 2,5-dioxidobenzene-1,4-dicarboxylate) and Zn<sub>2</sub>(dobpdc) (dobpdc<sup>4−</sup> = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), using pulsed field gradient NMR spectroscopy. An increase in the pore diameter from 15 Å in Zn<sub>2</sub>(dobdc) to 22 Å in Zn<sub>2</sub>(dobpdc) is accompanied by an increase in the self-diffusion of CO<sub>2</sub> by a factor of 4 to 6, depending on the gas pressure. Analysis of the diffusion anisotropy in Zn<sub>2</sub>(dobdc) reveals that the self-diffusion coefficient for motion of CO<sub>2</sub> along the framework channels is at least 10,000 times greater than for motion between the framework channels. Our findings should aid the design of improved porous materials for a range of applications where diffusion plays a critical role in determining performance.

scholarly journals Time dependent self-diffusion coefficient of methane molecules confined into micropores structure of a sandstone

2019 ◽  
Vol 65 (2) ◽  
pp. 190
Author(s):  
F. De J. Guevara Rodríguez
Keyword(s):  
Diffusion Coefficient ◽  
Pore Structure ◽  
Pore Size Distribution ◽  
Pore Size ◽  
The Self ◽  
Time Dependent ◽  
Self Diffusion ◽  
Molecular Confinement ◽  
Trapped Gas ◽  
Self Diffusion Coefficient

In this work, the effect of pore structure of a sandstone on the molecular displacement of confined methane gas is analyzed. It was found that the self-diffusion coefficient of a methane molecule depends on the pore size distribution an their connectivity. In particular, the time dependent self-diffusion coefficient exhibits a maximum which is correlated with the effect of the molecular confinement. It was found that a sandstone with small pores and/or pores bad connected traps the gas more efficiently than other pores structures. This fact enable to understand the scattered values which the residual trapped gas saturation measures exhibit with different sandstones.

scholarly journals Self-diffusion scalings in dense granular flows

Soft Matter ◽  
2021 ◽  
Author(s):  
Riccardo Artoni ◽  
Michele Larcher ◽  
James T. Jenkins ◽  
Patrick Richard
Keyword(s):  
Shear Rate ◽  
Solid Fraction ◽  
Granular Flows ◽  
The Self ◽  
Granular Temperature ◽  
Restitution Coefficient ◽  
Self Diffusion ◽  
Diffusivity Tensor ◽  
Dense Granular Flows

The self-diffusivity tensor in homogeneously sheared dense granular flows is anisotropic. We show how its components depend on solid fraction, restitution coefficient, shear rate, and granular temperature.

scholarly journals Self-Diffusion Coefficients, Aggregation Numbers and the Range of Existence of Spherical Micelles of Oxyethylated Alkylphenols

2021 ◽  
Author(s):  
Victor P. Arkhipov ◽  
Natalia A. Kuzina ◽  
Andrei Filippov
Keyword(s):  
Aqueous Solutions ◽  
Diffusion Coefficients ◽  
The Self ◽  
Self Diffusion ◽  
Aggregation Numbers ◽  
Temperature Ranges ◽  
Spherical Micelles ◽  
Limiting Values

AbstractAggregation numbers were calculated based on measurements of the self-diffusion coefficients, the effective hydrodynamic radii of micelles and aggregates of oxyethylated alkylphenols in aqueous solutions. On the assumption that the radii of spherical micelles are equal to the lengths of fully extended neonol molecules, the limiting values of aggregation numbers corresponding to spherically shaped neonol micelles were calculated. The concentration and temperature ranges under which spherical micelles of neonols are formed were determined.

Direct determination of the self-diffusion mechanism in bccβ-titanium

1989 ◽  
Vol 39 (8) ◽  
pp. 5025-5034 ◽  
Author(s):  
G. Vogl ◽  
W. Petry ◽  
Th. Flottmann ◽  
A. Heiming
Keyword(s):  
Diffusion Mechanism ◽  
Direct Determination ◽  
The Self ◽  
Self Diffusion
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